Processing facilities are typically managed using process control systems. Among other functions, these control systems often regulate the temperature of materials, particularly fluids and/or gases, undergoing a catalytic process in a mixing vessel in the processing facilities. For example, the temperature may be controlled by measuring the temperature of a fluidized bed of catalyst and increasing or decreasing the flow rate(s) of material(s) into the mixing vessel in order to raise or lower the temperature. Exemplary processing facilities include manufacturing plants, chemical plants, oil refineries, and ore processing plants, among others.
Conventional process control systems typically measure the temperature of a fluid or gas in a mixing vessel by means of a temperature probe that contacts the gas or the surface of the fluid. Alternatively, the temperature probe may be placed in the wall of the mixing vessel and contact the outer perimeter of the gas or fluid. However, neither of these arrangements provides an accurate temperature profile in a process reactor that has a fluidized bed of catalyst. These types of processes are often exothermic or endothermic in nature and a substantial difference in temperature may exist between the center region of the catalytic material and the surface or outer perimeter of the gas or fluid. However, due to high temperatures and/or the corrosiveness of materials in the mixing vessel, it may not be practical to place a temperature probe in the interior region of the mixing vessel and run wiring to the control system on the exterior of the mixing vessel.
Therefore, there is a need in the art for improved apparatuses and methods for measuring the temperature of materials in a processing system. In particular, there is a need for a temperature probe that can measure temperatures in a fluidized bed of catalytic materials in the interior of a mixing vessel without requiring extensive wiring to communicate with a control system on the exterior of the mixing vessel.